The present invention relates to crimping tools particularly to hydraulic crimping tools for affixing electrical connectors to wire transmission lines.
Hydraulic tools of this kind have been used for a number of years, as for example, Burndy Corporation HYPRESS Models Y35 and Y35-2. These tools include hydraulically driven dies for criaping electrical connectors onto transmission lines or for splicing transmission lines.
An hydraulic tool of this kind includes a head member containing the crimping dies which can be rotated 180.degree. relative to the operating handles for ease of positioning the crimping dies over a workpiece. The hydraulic tool is operated by placing the dies in position over an electrical connector, rotating a reservoir handle to advance a movable die into position on a connector and then pumping the operating handle to develop sufficient hydraulic force enabling the dies to crimp the connector. Approximately twelve tons of force are developed at the die head during a crimping operation. After crimping is complete, the tool is disengaged by releasing the hydraulic pressure, and retracting the dies.
In hydraulic tools of this kind it is desirable to provide for rotation of the die head with respect to the operating handles in order to improve utility of the tool particularly enabling the operator to position the crimping dies over connectors while maintaining a safe and convenient posture for operating the tool. A rotatable die head enables the operator safely and conveniently to engage and crimp connectors which are difficult to reach.
The Burndy Y35/Y35-2 HYPRESS models have rotatable die heads, however, the rotation is limited to 180.degree. relative to the operating handle.
Rotatable heads for hydraulic press tools are revealed in prior patents of which Swanson U.S. Pat. No. 2,821,877 is illustrative. In Swanson the die head is fully rotatable with respect to the hydraulic tool handle. The upper die is affixed to a C-shaped die head and the lower die is attached to a piston ram located within a cylinder formerly in the upper body portion of the tool. The die head and the piston ram are interlocking by a bolt member so that upper and lower dies are fully rotatable while the dies maintain working alignment. The design disclosed in Swanson involves rotation of the piston ram within a stationary cylinder and results in conflicting design requirements, viz., a fluid tight hydraulic power system and ease of rotation of piston ram. Swanson utilizes a set of ball bearings for rotating the die head on the stationary upper body of the tool. The bearings and their retaining grooves must also withstand the full crimping force developed between the die head and the tool during crimping operations. Additionally, in rotating the piston ram must prevent rotational stress from occurring in an internally mounted ram return spring. Swanson does this by means of a ball detent engaging the end of a spring retaining bolt. While the ball dent accommodates piston ram rotation, it is also called upon to prevent axial movement of the spring retaining bolt against the large axially directed clamming force developed by the power tool.
The result is a complex design in Swanson where many parts are called upon to serve several conflicting functional requirements.